Mike Tyson (right) gets set to launch an attack on Michael Spinks.
There was a time that boxing, horse racing and baseball were the only three professional sports that mattered in the United States.
Those days are long over. In boxing's case, it is in a straight-up fight for survival, as many of the top combat athletes have gone to mixed martial arts, and the legendary boxing matchups that used to rule the sports world are few and far between.
The sweet science of boxing is often a battle of strategy and will when top fighters get together. However, strategy doesn't always come into play. Sometimes the stronger and more powerful puncher just blows through his opponent and scores a knockout in the first round.
Here's a look at six of the most meaningful and impressive first-round KOs in boxing history.
Note that you won't see Muhammad Ali's first-round KO over Sonny Liston in this piece because of the controversial ending to that fight. While some claim that Ali's quick right hand that put Liston away was a clean punch, others say it wasn't hard enough to crush a grape and Liston went down out of convenience. With that in mind, the controversy holds it back from ranking with the fights we have listed.
Going into this June of 1988 fight, Mike Tyson was the established heavyweight champion in the eyes of the public, although Michael Spinks had taken the title from Larry Holmes three years earlier.
That gave this bout credibility in the eyes of the public. Spinks was undefeated and viewed as a clever technician in the ring.
Tyson had incredible power, and he was more than willing to put that characteristic on display. Tyson quickly disposed of his opponent with a series of punches that appeared to destroy Spinks' will to compete. Spinks was never the same kind of fighter after this bout.
Floyd Patterson was the heavyweight champion in September of 1962 when he took on hard-hitting challenger Sonny Liston at Comiskey Park in Chicago.
In addition to outweighing Patterson by 24 pounds (213-189), Liston held a 13-inch reach advantage. Liston's power was obvious in the early going with his thumping jab that got Patterson's attention right away.
Liston hit Patterson with a powerful left hook nearly halfway through the first round and then got in a series of clubbing punches that hurt the champion. Sensing that Patterson was hurt, Liston let loose with a powerful left hook, followed with a grazing right and then put him away with a finishing left hook to end the fight and take the championship in the first round.
Jack Dempsey was a full-fledged celebrity in the first half of the 20th century and is recognized as one of the hardest punchers in boxing history. One of his most famous fights was his devastating victory over champion Jess Willard, a much bigger man who absorbed one of the worst beatings in boxing history.
To earn a fight against Willard, Dempsey had to fight Fred Fulton, the other top heavyweight contender. Fulton was also a huge puncher and Brian Wilbur of Ring Side Report said Fulton was a 2-to-1 favorite. Dempsey knocked him out in the first round of their 1918 bout.
(The video above is a compilation of Dempsey highlights that illustrate his punching power.)
When Carl "The Truth" Williams challenged Mike Tyson in their 1989 bout, the challenger knew that he was going up against a devastating puncher.
However, he could not have possibly known that he was facing Tyson when he was at the peak of his career.
Williams was a solid boxer and a good puncher in his own right, but he had a tendency to get hit with left hooks. That's not a good thing when you went into the ring against Tyson.
Williams was the bigger boxer with the longer reach and he tried to establish his jab. About midway through the first round, Tyson winged his second left hook of the fight—the first one missed—and it caught Williams flush on the jaw. The challenger went down hard.
While he made it to his feet before the 10 count, he could not answer any questions from the referee and the fight was stopped.
Rocky Marciano was a powerful puncher but a somewhat awkward boxer throughout his career.
He had won the heavyweight championship from Joe Walcott by knocking him out late, after the champion had dominated for most of the fight. Marciano's power rescued him from defeat in that bout, and it was expected that Walcott would once again present a formidable challenge when they met in 1953.
During the first round of the rematch, Walcott used his jab effectively and seemed to avoid most of Marciano's punches. However, Marciano caught Walcott with a solid combination in the final minute of the round and put Walcott down for a 10-count. Walcott thought he beat the count and stormed around the ring, but the knockout was official.
This was the rematch of a 1936 fight in which Max Schmeling had registered an upset victory over Joe Louis.
Louis got his revenge in this 1938 fight at Yankee Stadium. Louis was the heavyweight champion of the world and was determined to show Schmeling that the first fight had been a fluke. Louis, a solid boxer and a devastating power puncher with both hands, was in peak condition for this bout.
He was ready for action at the opening bell and he bided his time as he looked for an opening. After Schmeling hit him with a left hook, Louis let loose with a barrage of punches that devastated Schmeling. He had no answers for the onslaught and he went down three times from right hand punches before the bout was stopped.
The fight was one of the great moments in boxing history. Schmeling was seen as a symbol of Nazi Germany as Hitler rose to power. Louis was the great American hope and also a hero for African-Americans.
The build-up for the fight was dramatic and Louis delivered one of the most impressive performances in boxing history. More than 70 million people listened to the blow-by-blow description of Clem McCarthy on the radio, according to NPR.org.